Hi Dick --
Good luck on your 4-1000A amplifier. I built one
back in the 70s and you can see it at:
1000A%20Amp/4-1000a1.htm
I was going to mention a cost-saver for you since
you mentioned about building your amp a low cost.
Many years ago I read a suggestion, I believe in 73
Magazine, where a fellow suggested using a 1 gallon
pickle jar as a replacement for the more expensive
Pyrex chimney for a 4-1000A. He cut out the bottom
and enlarged the top and claimed it fit the air socket
just fine. At the time I read that I think my regular
Pyrex chimney cost me $12 but I put that bit of
information in the back of my skull in case I ever
needed to have another one or a replacement. So
far I've never had to use it.
You mentioned that you already had a chimney so
you won't need that bit of info either but it might be
worth remembering for something.
The plate choke I used in my amp was commercially
available but I don't recall the manufacturer. They
probably aren't in business now anyway. (Oh no....I
hope that doesn't resurrect the recent thread on the
ham_amplifier reflector which had nothing to do with
ham_amplifiers.)
Good luck on your project. There's nothing quite like
the feeling you get from throwing the switch on a
3500+ volt power supply connected to a newly-build
but totally-untested amplifier. You've heard about
people who saw their whole life flash before their
eyes? That's similar.
73,
Jim - K5LAD
On 4 Jan 2007 at 17:05, Rich & DJ wrote:
Back to Radio / Amp stuff
Hello all you smart people, I don?t have any electrical
training but I am slowly building an amp from my junk
box. The power supply is complete. I enjoyed the
information about "glitch"protection and did a cut and
paste of all the important notes, making my information
list to build by. I will use a 50ohm resistor and a small
gage wire as a fuse in the HV line. I will also put in a
fuse c/t of the filament / bias line. I don?t have much
money (retired) to buy but a lot of stuff to build with. My
next thing to figure out is the plate choke for a 4-1000A,
I plan on about 3500v, first test, it nothing goes up in
smoke I can later up the voltage to 4500. The amp will
be a mono-bander at first, 21Mhz. With out a dip meter
is there a simple way to build a HV plate choke. I will
not load it to the max , just trying to make something
work.
Rich , kd0zz
"It's so simple to be wise. Just think of something
stupid to say and then don't say it." -- Sam
Levenson
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